In this research report, the influences of handedness, hand position while writing, and familial sinistrality (presence of left-handed relatives) on children's intellectual, reading, and visual-motor performance were investigated. Forty left- and right-handed children between the ages of 7 and 10 served as subjects. To assess hand positions, an index was devised, reflecting whether the subject's pencil pointed away from the body (normal position), was approximately parallel to an imaginary line drawn shoulder-to-shoulder through the body (horizontal position), or pointed toward the body (inverted position). Subjects' history of familial sinistrality was assessed through parent questionnaires; their intellectual functioning was measured by the Slosson Intellectual Test. Subtests of the Science Research Associate Achievement Test Battery and the Wechsler Intelligence Scale for Children-Revised were used, respectively, to assess subjects' reading ability and visual/motor performance. Results indicated that left- and right-handed children with horizontal hand positions had lower scores on reading ability than their counterparts who had inverted or normal hand position. Furthermore, both left- and right-handers with a positive history of familial sinistrality had higher IQ and spelling scores than children with no such history. Finally, no group differences in visual-motor performance were noted. Results are discussed in terms of hemispheric organization and the developmental reading process. (Author/MP)